This program project intends to combine the efforts of the members of the Radiopharmacy Program, the Division of Nuclear Medicine and those of collaborating scientists towards a comprehensive study of radiopharmaceuticals and related aspects of cancer diagnosis and management, with goal of: a) Improving existing agents and methods for tumor detection using single or multiple radiopharmaceuticals, and to evaluate the efficacy of scintigraphic methods of cancer diagnosis. b) Developing a better understanding of the principles and possible molecular mechanism of tumor localization of radiopharmaceuticals for tumor diagnosis, including the study of specific organs, e.g. liver, brain and pancreas. c) Continue with its attempts to optimize cancer chemotherapy using radiopharmaceuticals, based on pharmacological and body composition parameters. d) Studying the potential of stable nuclides as tumor localizing pharmaceuticals. This concerted effort has been categorized into 8 specific projects dealing with these general objectives. Studies to be conducted will range from basic science studies of the molecular mode of action and mechanism of localization of radiopharmaceuticals, to their clinical implementation at the patient level. Clinical problems will be analyzed for their chemical, biochemical, and pharmacological foundations, simultaneously with implementation of basic science concepts at the clinical level. The projects are all thematically interrelated and by being integrated into a comprehensive program, cross fertilize and strengthen the overall activity.